Conventional tire presses of the "slide back" or "tilt back" type normally employ loaders at the front of the press which are operative to pick up a green or uncured tire from a loading stand in the front of the press and position it on or closely adjacent the bottom mold section of the press, when opened.
In loaders such as seen in Mallory et al U.S. Pat. No. 3,065,503, the loader may be mounted on a carriage vertically movable on rails in turn mounted on brackets secured to the press head. Vertical movement of the carriage is obtained by a chain drive. Horizontal movement of the carriage is obtained by the opening and closing of the press head.
In tilt back type presses, the loader carriage may be mounted on fixed stanchions at the front of the press, but the carriage is nonetheless again driven by a chain drive. Reference may be had to Barton et al U.S. Pat. No. 3,924,983 for an example of a loader for such tilt back press. Horizontal movement is obtained by a carriage mounted on the vertically movable chain drive driven carriage, such horizontal movement being obtained by a cable piston-cylinder assembly.
Other types of loaders for other types of presses have been utilized. For example, there is illustrated in Gazuit U.S. Pat. No. 3,350,196 a rolling beam servicing a series of presses which incorporates an uncured tire chuck mounted on a rod-type post. Gazuit indicates a conventional screw or rack-type mechanism may drive the post. Cantarutti U.S. Pat. No. 4,025,251 also illustrates a tire press utilizing a rolling beam loader with the chuck mounted on a vertically oriented piston-cylinder assembly. Such loaders are normally quite adequate for the production of conventional tires and generally achieve, to applicant's knowledge, a degree of precision and accuracy which might normally be measured in fractions of an inch. However, such loading tolerances are unacceptable in the precision production of radial tires or modern machining or assembly utilizing the transfer of heavy round objects. In the tire vulcanizing process, excessive tolerance in the loading of the uncured tire may result in bead distortion or misalignment of the uncured tire with the mold sections and the bladder center mechanism. Since tires are quite heavy, especially truck tires, it is important in the loading process to be able to move the tire from one position to another in a short time and stop the tire in the desired position with a repeatable accuracy of, for example, plus or minus 0.005 inches.